Cannot change margins in Continuous mode

[gbitzes]

When Continuous mode is seleted, I am not able to change the margins, and the text always occupies the entire width of the screen.

I'm really used to scrolling when reading text on a screen, I'm not comfortable having pages.. I'd rather use Continuous mode, but it's a bit tiring to have my eyes travel a rather large horizontal distance for each line. Changing the margin option seems to have no effect when in this mode. (I'm using the latest commit of branch develop)

Any plans to fix it? Thanks!

[danielweck]

Thank you for your feedback.
We definitely need to fix support for "margins" in the Chrome app / cloud reader (things are a little different in native launcher apps, which do not use the same "margin" heuristic as found the readium-js-viewer preference dialog's slider).

1. in paginated reflowable documents, the width of a run of text (column width) is limited by a maximum value (just as you say: to offer comfortable horizontal eye scanning across the screen), and there is also a minimum threshold to ensure that a single column in two-page synthetic spread mode does not shrink so narrow as to become unreadable (in which case there is an automatic switch to single page).

2. in scroll mode, the document occupy the full viewport width, with no application of either margins (whitespace padding) or maximum width limit, resulting in potentially long lines of text.

To fix this, I think that we need to allow users to configure the min/max thresholds (or at least the max one, in order to minimize UI / configuration complexity), and we need to apply that same logic to the scroll view. Fixed layout documents are treated differently, as they obey layout rules that are more publisher-specific.

Note that right now, the "margins" slider in the preferences dialog does not behave in the same way that it used to (before the harmonization of the pagination layout in native launcher apps), resulting in confusing lack of visible whitespace change around the text. This is a known bug, see:
#179 (comment)

[danielweck]

This is an example from Gutenberg which shows how the lack of margins affects readability. Resizing the browser window is not always a possibility.

[danielweck]

Related: #498